It's YouTube Comedy Week, as anyone who looks at advertising on the side of London buses will know. For the rest of this week, we can expect videos and performances posted at the online video channel by the cream of American and British standup. Stars include Sarah Silverman, Andy Samberg (star of BBC3's Cuckoo and the Stateside favourite Saturday Night Live), Vince Vaughn, Owen Wilson and more, alongside a host of internet comedy names, including the Onion and Epic Rap Battles of History. It is "the biggest single comedy event in history", says Justin Gayner, executive producer of Comedy Week in the UK, citing YouTube's one billion monthly users.

The event launched last night New York time with the Big Live Comedy Show, a streamed floorshow featuring the likes of Tim and Eric and Edinburgh Fringe favourite and 30 Rock writer Hannibal Buress. Sarah Silverman hosted, feigning giddiness at the "totally unregulated" freedoms afforded her by performing exclusively for the internet. "I thought it would be funny to see how far we can go without any consequences," she says, before pretending to slit the throat of a production assistant and stab co-host Seth Rogen in the guts.

The highest profile among this morning's YouTube Comedy Week releases, of course, is Learn Guitar with David Brent, the first of a series in which Ricky Gervais revives the most indelible of his alter egos. Other Brit comedy stars to be featured over the week include David Mitchell and, er, Jamie Oliver. "There are going to be some amazing surprises during the week," according to the pre-publicity, which included this video of Arnold Schwarzenegger ("what you didn't know was, I'm a big fan of comedy") being exaggeratedly manly for laughs. We're aiming to cover the lot, so watch this space for the latest on Youtube Comedy Week – and let us know the best (and worst) of what you've discovered out there too.